Die roll and die rolling



W. P. WITH EROW Sept. 21

' Filed Feb. 29, 1924 Patented Sept. 21,, 1926.

UNITED STATES PATENT OFFICE. t

WILLIAM r. wrrnanovg, or rir'rsnnaen, PENNSYLVANIA, ASSIGNOB To wrrnnaow srnnL comrm, or NEVILLE ISLAND, PENNSYLVANIA, A conroiwrion or PENIISYLVANIA.

nm'aoLL am) nm- ROLLING.

Application flled' February 29, 1924. Serial No. 695,964.

This invention relates to die rolls and die rolling, and particularly to the formation of matrix portions in die rolls in a way which more closely achieves desired dimensions in the variousportions of the product. I have found that the elongation produced by any particular sectionof a pair of die rolls, while it varies generally with the percentage of reduction from the lead- .er, will also vary in accordance with the dimensions of a preceding section, particu larly if there is a considerable difierence in area between suchsections.

I believe this to be due to a heretofore uncompensated action of the die rolls on the leader from which the die rolled articles are produced. While ordinarily the ratio of length of a leader to the length of a finished article varies with the ratio oftheir cross sectional areas, this apparently does not entirely hold true where sudden changes.

in section of the finished articles are encountered, as in die rolling. Seemingly the metal piles up prior to entering the rolls, 3

so that considering only the portion of the leader immediately adjacent the rolls, the finished article is virtually being produced from a leader of greater cross sectional area than the leader which is furnished to the mill. Such being the case, what happens is that if a roll portion designed to produce a larger cross section .is encountered, the result will be as though for a very short 'period the article were being produced from a leader of larger dimensions and such portion woiild, therefore, be longer than would be expected by the ordinarycalculation of lengths by percentage reduction. This is shown very clearly in .actual practice, and -I have" found that when did rolls are designed to,compensate for this action, die rolled articles may be produced within exceedingl close dimensions.

The a ove theory 1 borne out by the rolling of various articles and I have found that it is even possible to producea section having portions of a larger cross sectional area than that. of the leader supplied to the mill, a section havin an excess of ashi-ghas 8 to 10 per cent avigg. been produced in regular -.0 erationr I-Iiiwever, I do not limit myself this theoryl' {AS abovestated, I have found that when the mill and while still hot;

a section of a certain size is followed'by a section of larger size it is necessary, if ac-' curate results are to be produced, to shorten the matrix portion which is to produce this larger section. Otherwise, the rollportion will be longer an the calculated size. When conditions are reversed, the action of the preceding section on. the succeeding section is also reversed. That is to say, ifjafter rolling a large section we cometo a smaller section, the calculated length of the roll matrix portion for such "smaller section should be somewhat increased.

In the accompanying drawings which ill lustrate more or less' diagrammatically a few of, the applications of my invention- Figure 1 is a view of a portion of a series of die rolled axle blanks as they Figure 2 is a corresponding view of a trimmed axle blank when cold; I

'-Figure,.3 is a developed'view of a die roll.

for producing. the strip of Figure 1;

Figure 4 is a section to enlarged scale of a leader from which the strip of Figure 1 is rolled;

Figure 5 is a section to the same-scale on line V'V of Figure 1; 1

Figure-6 is a side elevation of a series of die rolled horseshoe blanks;

Figure 7 is adiagrammatic view Showing the roll matrices from which the blank of Figure 6 is produced these, however, be-

ing shown as in a strai ht instead-ofin a circular manner as in t e roll itself;

Figure 8 is a side elevation of adie rolled 'axle blank; and

Figure 9 is a view similar to Figure 7 and showing in diagrammatic form one of a pair of identical rolls for producing the axleblank shown in Figure 8.

In laying out a pair of rolls for producing come from the axle blank shown in Figure 2, the length of the article atthe rolling temperature is first calculated. A leader of suitable size is then selected and the various portions of the roll matrices are then calculated in view 1y symmetrical and if the matrix portions were calculatedbolel by taking into account l of the reductionfor any particular section I from such leader. ,In this particular case the article to be produced is antero-posterialof Figure 3, it will be found that I livery speed is consideraby' r area of the leader, the roll layout would also be symmetrical. As above set forth, however, such a roll will not produce a symmetrical axle blank but instead will produce. 5 a blank with one end portion widely varying in dimensions from the other. Figure 1 shows the axle blank with its flash as delivered from the mill, the arrow indicating the direction of. rolling. This blank is symmetrical and differs in dimension from the trimmed blank of Figure 2 only by a factor due to temperature difference. If either of these figures, however, is compared with Figure 3 bytaking off dimensions with a pair of dividers and making comparison with the dimensions of corresponding matrix portions in theroll layout 7 a number of apparent discrepancies occur. The roll layout of Figure 3 will be found asymmetrical, particularly in the end. portions, this variation being due in each case to compensation having been made for the dimensions of .a preceding section. For example,

25 in the finished product the distance marked A is 1.7188 inches and the corresponding distance on the hot blank will be such dimension multiplied by a temperature factor. Also, this dimension will be found the same on eitherend of the blank. However the roll matrix portion A' in the leading portion of the roll is'1.6744 inches long, while i .the correspondingportion A on the following portion of the roll is only 1.5843 inches long.

These differences in dimensions are due to the differencev in cross sectional area of the preceding sections. A section on the chain line ss in Figure 1 is only1.33 square inches in area on the finished product, while a section on the line -s is 2.95 square i1iches in area. This difference is reflected in the elongation of the article immediate- -1 succeeding such sectionand the dimcn 810113 A and A are accordingly varied to v compensate for such difference.

Figure 4 shows a cross section of the leader from which the die rolled strip of Fi ure 1 is produced, and the actual area of suc leader is 3.22 square inches. Figure 5 3 shows the cross section of the largest portion of theaxle blank as produced and its area .as rolled is 3.48 square inches. It will be seen that this re resents an excess over the area of the lea er of approximately 8 per cent and bears out my belief that the metal piles u just before 1t enters the rolls when a smal section is being rolled and is squeezed in on an abrupt change from a lai section to a smaller-one. o statethe matter in another way, the entering speed of the leader is generally near the peripheral speed of the rolls and the dein excess, depending upon the amount 0 eductioit The section of the article is encountered the forward slippage does not exactly correspond to this difference in area as indicated by the difi'erznce in the lengths of the portionsAf and Referring to Figures 6 and 7; the dimensions B in the rolled article are each 3.875

inches while the corresponding matrix dimensions B and B" .are 3.952and 3.702 respectively. In both of the above described examples'it will be seen. that symmetrical articles are produced by providing non-sym- "metrical rolls, or that spaced apart equal portions are iolled by providing unequal roll matrices corresponding to such portions.

Figures 8 and 9 show an axle blank and a straightline diagram of the roll used in its product-ion. In Figure 8'there are indicated-two dimensions C and D of substantially the same cross section but preceded by portions of'considerably difi'erent cross sectional area-. For example, the area of the section immediately preceding the portion C is 1.418 square inches, while the maximum section is just ahead of the portion D and is 3.976 square, inches. The correspond- I ing dimensions C and D vary from the dimensions C and D in diflerent amounts and this isdue to the difference in area. of the preceding section. In this particular case the ratio of C to C differs from the" ratio of D to D by a little over 8 per cent, this compensation in the multiplying factor being largely influenced'by the difference in area of the preceding sections.

My invention -makes it possible to; more into account an important item in design accurately calculate die rolls since it takes which has heretofore been neglected with a corresponding expense the production of accurate and entirely satisfactory die rolls. A large amount of the variation of .roll matrix portions from calculated dimensions which have heretofore been made in a more or less haphazard fashion according to the experie'nceof the roll designer is reduced to a definite rule of action, which may even be resolved into a mathematical compensation after the results of a number of similar rolls have been checked and properly applied.

A complete understanding of my invention makes it possible to. better select the size ofthe leader to be employed. As pointed out herein, it is entirely feasible to die roll an article having amaximum section which is-larger than the-leader from' which it is prddu'ced. This is of great ad- I vantage, since the amount of. reduction to be efiected is considerably reduced and a' I material reduction in the operation and upkeep'of the mill. may be efiected,"not only by reducing the strain on the working parts and in the power required, but also by reducing the amount oi,- flash which is produced in such operation.

It will be understood that the dimensions given in the various examplesare not 'fixed and unvarying but are likely to vary in accordance with a large numberfof other factors, as willvbe readily appreciated by' those skilled in the art. However, they are illustrative of the principles involved and clearly show the importance of making allowance for 'the'dimensions of a preceding section: a

application is While I have illustrated the invention as applied to a few articles commonly produced by die rolling, it willbe understood that its far beyond these forms and may beapplied to other die rolled articles within the scope of thefollowingclaims.

I claim: 1. In the method of making die rolls, the steps consisting in varying the dimensions of a roll matrix portion from the theoretical dimensions of such portion as calculated by reduction from the leader, such variations being made to compensate for the change in extrusion effect due to the difference in cross section or shape between a ortion preceding the portion in question uring the roll ing operation, and the portion in question.

2. In the method of making die rolls, the steps consisting in varying the dimensions of a roll matrix portion to compensate for the change in extrusion efiect due to the difference in cross section or shape between a portion preceding the portion in question dursection or shape between a 'ing the portion in question uring the rolling'the rolling operation, and theportion in question.

3. In he method of making die rolls, the steps consisting in compensating for forward slippage in a roll. matrix p'ortion by varying the -dimensions of a roll matrix portion from the theoretical dimension of such portion as calculated by reduction from the leader to compensate for the change in extrusion efiect due to the dilfere'nce in cross ortion preceding operation and the portion in question.

4. Inthe metlmd ofmaking die rolls, the stepsqconsisting in varying the ratio of length of a portion to be rolled to the length of thematrix portion for'rolling the same from the theoretical ratio calculated in ac-' cordance with the percentage of reduction from the leader, such variation being made to compensate, for the change in extrusion "effect due to the difierence in cross section or shape between a portion preceding the portion in question during the rolling opera tion and the portion in question.

-.5. In the method of making die rolls for rolling antero-posterially symmetrical articles of varying crosssection, thesteps consisting in forming .pairs of corresponding matrix portions in the roll to produce the symmetrical articles and varying the dimensions of a-palrof such matrix portions one from the other to-compensate for the changev v in extrusionefl'ect due to the "diiference in cross section or shape between portions precedingthe portions in question during the rolling operation.

6. In the method of making die rolls for the production of articles having a pair of 3 equal portions connected by an intermediate portion of different dimensions, the steps consisting in forming matrix portions of unequal dimensions for the production of such equal portions, the unequal dimen-- sions being made to compensate for the change in extrusion efli'ect due tothe difl'erence in cross section or shape between the second of such equal portions produced by the die rolls and the intermediate portion.

7. In the method-of making die 'rolls"for rollinge articles of varying cross section and having a plurality of spaced apart equal portions, separated by an intermediate portion of difierent cross section the steps consistmg in providing unequal roll matrices corresponding to such spaced apart portions,

the difference in dimensions in such roll mat Y rices being made to compensate for the change in extrusion efi'ect due to the diiference 1n cross section or shape between the portions preceding such equalportions duringthe rolling operation.

a new article of manufacture, a. die roll having a matrix portion whose dimensions. vary from the theoretical dimensions to compensate forvthe change in extrusion effect due to the. difierence in'cross section or shape between a roll for the production of antero-posterially symmetrical articles, said roll having unuring' the rolling opsymmetrical matrix. portions, said matrix portions varying from one another to com- .pensate for the change-in extrusion efiect due to the-difierence in cross section or shape' between portions preceding the portions in. question during the rolling operation.

11. As an article of manufacture, a die for the change in extrusion efi'ect due to roll for the production of articles of varying the difference in.cross section or shape becross section having a plurality of spaced tween portions preceding the said spaced apart equal portions, the roll having unapart portions during the rolling operation.

.5- equal matrices corresponding to the spaced In testimony whereof I have hereunto set apart port-ions, the inequality in such mamy hand. trix portions being provided to compensate WILLIAM P. WI THEROW. 

